ISSN : 2454-9150 Design and Manufacturing of Unmanned ...

International Journal for Research in Engineering Application & Management (IJREAM)

ISSN : 2454-9150 Vol-07, Issue-05, AUG 2021

99 | IJREAMV07I0577024 DOI : 10.35291/2454-9150.2021.0435 © 2021, IJREAM All Rights Reserved.

Design and Manufacturing of Unmanned Aerial

Vehicle 1Sohan R. Dhake, 2Mihir R. Jadhav, 3Akshay A. Gite, 4Nilesh S. Dhikale

1,2,3,4Department of Mechanical Engineering, K.K.W.I.E.E.R.; Nashik, Maharashtra, India.

[email protected], [email protected], [email protected],

[email protected]

Abstract: In modern times, the entire world’s economy is driven by agricultural sector. Though technological

advancement in this sector have been prevalent for long time, it has been developing gradually over the period. This

project will aid the community in simplifying the process of spraying pesticides aerially and will also cover a huge

chunk of land mass from a single point. A remote-controlled UAV (Unmanned Aerial Vehicle) is used to spray the

pesticide to avoid the humans from coming in contact with harmful pesticides and toxic chemicals. The UAV is operated

by manual flight plans and the sprayer is manually triggered by RF (radio frequency) controlled Nozzle. Radio

Controller controls the movement and speed of the drone. This project describes the development of UAV using

additive manufacturing and the sprayer module. This model is used to spray the pesticide content to areas that aren't

easily accessible by humans. This drone system mainly works on the principle of thrust. The sprayer module will spray

the liquid pesticides over the field aerially. This project mainly concentrates on designing a low weight structure using

material which is recyclable, cost effective and less harmful to the environment that sprays pesticides for farming.

Keywords — Agricultural Sector, Unmanned Aerial Vehicle (UAV), Sprayer module, Pesticides, Radio Controller, Thrust.

I. INTRODUCTION

Drone Technology is emerging as a huge invention

accounting for the help in various fields. One of them is

agriculture. In the agriculture field, drones can be used for

numerous advantages such as soil and field analysis, seed

planting, spraying of fertilizers and pesticides on crops,

surveying and crop mapping, monitoring the fields health

and its management, etc. In this new era farmer’s

productivity and profitability has increased by using this

precise technology. Considering these aspects, a drone is

developed using an automated system and according to the

needs. This project aims to overcome the problems

regarding the weight of the frame and its suitability with

equipment used in the system. UAV’s were initially used in

military operations and this practice has made humans

develop systems that will be used in various applications.

The Indian service sector is the most substantial contributor

to the country's GDP. Contributing 18% to the GDP, it is

the prime source of livelihood for approximately 58% of the

country's population. Agriculture sector along with forestry

and fishing, results in a gross added value of around

Rs.18.55 lakh crore as of 2019. Regardless of its

contribution to the GDP, the country is yet to enhance

productivity and efficiency in the sector to reach its highest

potential. Unsuitable methods for monitoring crops,

irrigation, use of pesticides and many other necessary

farming activities are currently adopted. Resources are

inadequate, and are needed to be allocated according to

weather conditions to gain the return on investment. As the

governments and businesses across the world reorganized

the significance of food security and consequences of

environmental degradation, pollution, climate crises, and

water scarcity, the urgency to overcome certain obstacles

arose. Drone technology has widespread applications, and

unmanned aerial vehicles are widely popular in different

industries. Drones encourage farmers to receive plenty of

benefits through precision agriculture. And fill the gap of

human error and inefficiency by traditional farming

methods. The purpose of adopting dinner technology is to

exclude any guesswork or ambiguity and focus on accurate

and reliable information instead. Agriculture drones

empowers farmers to adapt to specific environments and

make mindful choices accordingly the data gained related to

weather, soil conditions and temperature, helps to regulate

crop health, crop scouting, crop irrigation, and crop damage

assessments [1]. Drone technology equipped with artificial

intelligence AI, machine learning ML, and remote sensing

features are rising in demand because of its advantages.

Typically, drones include navigation systems, GPS, multiple

sensors, programmable controllers, and tools for

autonomous drones. Unmanned aerial vehicles UAV s can

get more precise data than satellites, which are in use now

as introductory goods for farm management, for precision

International Journal for Research in Engineering Application & Management (IJREAM)

ISSN : 2454-9150 Vol-07, Issue-05, AUG 2021


agriculture. Drone technology quickly reestablishes

traditional agrarian practices. They give effective control on

fungus, insects, etc. It will help to increase the quality of

crops as well as production. According to this, the exact

amounts of chemicals needed to fight the infestations are

known, and this helps diminish the costs inflicted by

farmers. Additionally, through drone crop spraying human

contact with harmful chemicals will be limited. And agri-

drones can carry out these tasks much quicker than agri-

vehicles. Boost productivity, mitigate input costs and

ultimately maintain a good quality crop drones are novel

agro-tech tools to assess the crop health and eradicate fungi

from the farms [4].

In today's growing world, the agriculture sector is going

to become a good income source as well as a good source

for foreign exchange and it will help to grow our economy.

Agriculture, with its allied sectors, is the largest source of

livelihoods in India. 70 percent of its rural households still

depend primarily on agriculture for their livelihood, with 82

percent of farmers being small and marginal [7]. Currently,

techniques such as photogrammetry, machine learning and

vegetation indices are being used in advancing the

development of mapping, irrigation and monitoring. [10]

II. BASIC COMPONENTS USED IN DRONE

a) Frame of the Drone - Frame is used for mounting of all

the accessories and equipment that will be useful for

it. It also ensures the stability of the drone according

to its design.

b) Brushless Motors - These motors help to lift off the

drone from the ground position and also to maneuver

accordingly.

c) Electronic Speed Controller (ESC’s) - Electronic speed

controller are the ones who get input of the speed

from the flight control board. As the name suggests,

these ESC’s control the speed of the motor.

d) Propellers - Propeller are mounted on the motors to

generate thrust and lift the drone.

e) Power Distribution Board- power distribution board is

used to source the power from battery to the motors.

f) Flight Controller Board(FCB) - Flight controller board

is used for mounting the extra accessories used in

drones like telemetry, GPS, etc. It acts as the brain of

the drone to give signals to other components.

g) Battery - This is the power source of all the

components who require electric supply to ensure

working of the drone. [8]

h) Transmitter and Receiver - Transmitter is a remote

control which is used for giving commands to the

drone and receiver is used to receive the transmitted

signals from the remote control and pass it to the flight

controller board.

These are some basic components used in drones to

ensure the drone function properly.

III. METHODOLOGY

A. Methodology Flowchart

Fig.1 Methodology Flowchart

Fig. 2 Block Diagram of Hexacopter

Selection of appropriate controller

and battery

Designing of 3D CAD model of the

system according to the components

selected

Input Study and Gathering

Requirements

(Payload of craft 4.5kg)

Calculation of total weight and

selection of Material

(Total weight of craft 4.5kg and

Material - ABS)

Calculating the thrust required

and selection of motor

Structural and Stress analysis of Drone

(Deformation of the frame)

Designing of Spraying Mechanism and

its placement with water tank

Manufacturing and Assembly of

Components

Testing

International Journal for Research in Engineering Application & Management (IJREAM) Volume XX, Issue XX, MMM YYYY.


101

Fig.3. Block Diagram of Spraying Module

B. Components Description

Frame Components

i) Frame:

1. It is relatively inexpensive.

2. It is famously durable.

3. The centre plate doubles as a power distribution

board which tidies things up quite a bit and allows me

to get rid of my ugly DIY wiring harness.

Things to consider here are weight, size, and materials.

They’re strong, light, and have a sensible configuration

including a built-in power distribution board (PDB) that

allows for a clean and easy build.

Frames can also be built at home using aluminium or balsa

sheet. But results will vary from manufactured frames, both

aesthetically and in terms of flight attributes.

Fig.4. Drone Frame

ii) Motors

Motors used in drones are brushless DC motors. BLDC

motors have longer life as compared to others. And also

these motors can achieve higher rpm speeds. These motors

are rated in KV rating. KV is known as Kilovolt. Platform

of the drones also contributes towards payload capacity [5].

The motors also have movement in clockwise and anti-

clockwise direction. These motors are placed in

configuration as shown in the figure below.

BLDC motor designation

Ex- 1050 750KV

Here, 10 denotes the stator size of the motor and 50 is rotor

size. 750 KV is the KV rating of the motor. Lower the KV,

Higher is the torque generated.

Fig. 5 Configuration of Motors in Drones

iii) ESC’s

An ESC is an electronic speed control which regulates

and controls the speed of the motor. ESC are rated in

amperes. These regulate the current to the motors according

to the need. ESC’s receives signal from the flight controller

board to vary the amount of the current. These ESC’s are

selected as max. ampere rating of the motor multiplied by

1.5 factor. ESC are an essential component of modern

multi-rotors that offer high power, high frequency, high

resolution 3-phase AC power to motor in an extremely

compact miniature package

Fig.6. Electronic Speed controller

iv) Power Distribution Board

Power distribution board are also known as PDB’s. As the

name suggests, these are used to distribute the power to

motors and other accessories that are used in drone. Some

PCB’s are integrated in the drone frame which offer a great

feasibility in terms of wire connections and complex

structure. PDB’s are available in different ampere rating and

are selected on the basis of total ampere requirement of the

drone.



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Fig.7. Power Distribution Board

v) Battery

Battery in the drones acts as mitochondria. It supplies

power to PDB and PDB distributes the power accordingly.

Batteries are denoted in Mah ( milli-ampere-hour) rating.

Batteries can be used in series and parallel connections as

per the requirement of voltage and current. The greater the

Mah rating of the battery, greater the flight time of the

drone. These batteries are lithium polymer based batteries.

Fig.8. Battery

vi) Flight Controller Board

The Flight Controller Board (Pixhawk) acts as the brain of

the drone also known as FCB. FCB sends the signal to all

the other components. FCB has inputs of motor ESC’s. FCB

has attachments of FPV cameras, telemetry, GPS, etc [3]. It

is basically the nervous system of the drone which receives

the signal from the transmitter. Receiver is mounted on

FCB. This should be placed on a shock absorbing plate as

the shocks during the flight may affect the stability and

malfunction of the components. It supports 8RC channels

with 4 serial ports. It has 2mb of flash memory and 512kb

of RAM memory.

Fig.9. Pixhawk FCB with 915MHz telemetry, GPS,

Shock Absorbing Plate

vii) GPS

GPS is known as Global Positioning System. It improves

the stability of drone. It helps to determine the location of

the drone. The position provided by the receiver can be

used to track the UAV, or, in combination with an

automated guidance system, steer the UAV [6].

Fig.10. GPS

viii) Telemetry

Telemetry is used to provide the direction and path to a

drone. This can also be remotely activated by a mobile

device. Telemetry is available in 433 MHz, 915Mhz, etc.

Telemetry is a digital two-way data stream, which can both

send data about the flight down to a ground station (in our

case, the Mission Planner) and send commands up to the

autopilot. There are other ways to get telemetry data, such

as embedding it in the video stream of your FPV system

(called On-Screen Display) and, confusingly, some RC gear

offer a limited telemetry downlink, but by doing it with its

own radio link like the 3DR Telemetry kit, it arrives in a

full digital form that can be displayed, logged and analyzed

by the Mission Planner.



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Fig.11. 433MHz Telemetry

ix) Transmitter and Receiver

A transmitter is a device that uses radio signals to transmit

commands via set frequency using a radio receiver which is

connected to drone. A transmitter consists of many

channels. These channels can be used for purposes like

activating components like camera, pumps and other

accessories. Basic function of a transmitter is to control the

movement of the multirotor. An FPV Drone Radio

Transmitter commonly uses the following frequencies:

27MHz, 72MHz, 433MHz, 900MHz, 1.3GHz, and 2.4Ghz,

433Mhz, 900Mhz, and 1.3GHz are typically used in long-

range FPV and RC systems.

Fig.12. Transmitter Pin Diagram

Fig.13. Flysky FS-i6 2.4Ghz RC Transmitter

Fig.14. 6ch 2.4Ghz Receiver

C. Spraying Module:

i) Servo Motor

Servo motor will be used to regulate and control the flow of

water through nozzle. This will be connected to the flight

controller board which will receive the signal from the

transmitter. The end of the motor will be further attached to

the DC motor controller which will give power to the water

pump.

Fig.15. Servo Motor

ii) DC Motor Controller

DC Motor Controller is used to provide power to the water

pump. Now, this controller will receive a kinetic energy

from the servo motor which will be converted to electric

energy. So as the speed of the motor changes, the input

current supplied to the pump also changes and hence the

flow of water is controlled. This controller is available in

various configurations as per the requirement of voltage and

current.

Fig.16. DC Motor Controller



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iii) Water Pump

Water pump is used to pump water from the tank attached

to the frame of the drone. These are used to move water,

they play a fundamental part in agriculture as they move

water from its source to field and crops. Water is drawn into

the pump through the inlet side when pressure difference is

made within pump system. The water wants to move from

an area of high pressure to an area of low pressure.

Fig.17. Water Pump

D. Calculations:

Selection of Motor

An electric motor is an electrical machine which converts

electrical energy into mechanical energy. There are two

types of motors generally used for drones, they are

i. CW and CCW Motors:

Basically the difference between CW and CCW motors is

the prop shaft thread rotation. The intention is to use 3 CW

motors and 3 CCW motors on a hexacopter, so that when

the motors spin, all six prop nuts lock themselves down.

Thrust Calculations:

General required thrust is given by a formula mentioned

below it is,

Thrust required = (total weight) × thrust ratio

Here, the thrust ratio will be 2:1 because in most of the

agricultural drones speed is not a necessary criteria. Torque

is what we needed. In FPV or racing drones the thrust ratio

required is greater than 8:1 or 13:1 depending on the

requirement. [9]

= 4500 x 2/1

Thrust force required =9000 gf.

As frame is hexacopter,

Thrust force required per motor = 9000/6

= 1500 gf.

Now, we started searching for the motors that will produce

1500gf of force at 50-85% of throttle. Motor is never

chosen at 100% throttle because if in case you need an extra

amount of thrust then you will be able to use it. It is

considered as a factor of safety while searching for motors.

We found an I-rotor 5010 750KV motor which produces

1456gf at 85% throttle.

Tab.1. Motor Thrust Test Chart

We have calculated the thrust force in above steps. By

considering the value of thrust force, we have checked the

table and selected the suitable configuration.

Calculations for an ESC:

ESC = 1.2-1.5 x max amp rating of motor.

= 1.5x22.4

= 33.6A

So, we selected ESC of 40A.

That is Ready to Sky 40A opto ESC.

Opto ESC’s are more durable and are highly insulated

Battery Calculations:

As we know from the motor thrust chart that we need only

4S battery i.e. 4 cell battery.

If we consider a 4S 5200mah battery, then it will supply a

continuous current of 20.8A for 15 minutes. We need 0nly

18.5A of current to achieve 2:1 thrust ratio. So our flight

time will increase to 16-17 minutes. We can also use larger

batteries than 5200mah to increase flight time considering

the cost of total drone equipment as per the need.

We have to calculate the amount of energy it is consuming;

hence we have now calculating the source required by the

battery.

Max source = discharge rate*capacity

= 20×5200

= 104000

= 104Amp

Discharge rate:

Discharge rate is simply how fast a battery can be

discharged safely. In the RC Li-Po battery world it is called

the “C” rating. Remember we should never discharge a Li-

Po BATTERY BELOW 80% OF ITS CAPACITY.

So, the max source i.e. ESCs should not exceed 104A, since

we have selected a 40A ESC there is no problem, it is a

perfect battery.

Propeller Calculations for Thrust:



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We have, Payload Capacity + The weight of the craft

itself = Thrust * Hover Throttle %

4500 = T×85%

T = 5294 gf

This amount of thrust should be provided by 6motors, so we

can calculate individual thrust required by,

T = 5294/6

T = 882.33 gf

Since the thrust required is 882 gf, as we calculated above

thrust produced or generated by each motor is 1500 gf. The

system will be safe or run without any default.

Finally, we have concluded to select the 6 propellers of size

12×3.8 inch which 3 are supposed to CW and others for

CCW as mentioned in the motor thrust chart.

3D CAD Design Parts and Assembly:

The design of Hexacopter has been done by using

Solidworks 2020 software. The design is done in such a

way that there should not be any damage to the propellers,

motors and mechanical equipments. The central hub, spars

and the arms are designed individually and assembled.

Fig. 18. CAD Model - Base/Top Plate

Fig.19. CAD Model – Arm Support

Fig.20. CAD Model - Arm

Fig.21. CAD Model – Landing Gear

Fig. 22. Assembly

Fig. 23. Bill of Materials



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IV. ANALYSIS

Drone Frame Structural Analysis:

Load Conditions:

Load at Centre of the Frame

Load at Arm End

Material Properties – ABS Plastic

Tab.2. ABS Material Properties

Why only ABS?

ABS is 25% lighter than PLA. PLA is string and stiff but

ABS is tougher. ABS is more ductile with higher flexural

strength and better elongation before breaking. ABS is more

suitable for heat resistance as PLA can lose its structural

integrity. ABS has glass transition temperature of 105⁰C

whereas PLA has glass transition temperature of 60⁰C. Cost

of ABS is also cheaper than PLA and it is readily available

everywhere.

Loading Conditions:

Fig.25. Thrust Force

Fig.26. Tank Weight Load and Motor Thrust

Meshing:

Fig. 27. Meshing

Fig.28. Deformation Before Modification

Total Deformation – 1.92mm

Total Deformation After Modification:



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Fig.29. Deformation After Modification

Total Deformation After Modification – 1.68mm

Fig.30. Stress Analysis on Frame Before Modification

Equivalent Stress = 4.18Mpa

Maximum stress value: - 3.1 MPa

Allowable Yield Strength: - 4.14 MPa

Allowable Ultimate Tensile Strength: - 4.43MPa

Equivalent Stress After Modification:

Fig.31. Stress Analysis on Frame After Modification

Equivalent Stress After Modification = 3.1Mpa

Maximum stress value :- 3.1 MPa

Allowable Yield Strength :- 4.14 MPa

Allowable Ultimate Tensile Strength :- 4.43MPa

Maximum induced stress is less than allowable stress for

material.

According to the above analysis, we are assured that our

design is safe and ready to use. This also concludes that

additive manufacturing technique can also be used for

manufacturing drones. Additive Manufacturing Technique

allows the users to modify the design according to the

purpose and help the environment by causing no waste and

harm. The cost is also too low compared to other techniques

and materials which is a bonus for 3D printing.

Result and Conclusion of Analysis:

1. Total Deformation Value is 1.68 mm at ARM

end.

2. Equivalent Stress Value is 3.1 MPa, which is

much lower than yield strength & ultimate

strength of the deployed material.

3. After drone frame modification, total

deformation and equivalent stress have

reduced by some amount.

In conclusion, given drone frame assembly is

Safe and Stable for the given loading

conditions.

V. FUTURE SCOPE

1. Weight lifting capacity of the Hexa-Copter can be

increased by increasing-

• The number of motors.

• The propeller size.

• Rating of the Motor.

2. Flight time can be increased by increasing the battery

capacity.

3. Pesticide carrying capacity can be increased by

increasing the size of the tank.

4. Development of Nozzles. (i.e. rotation of nozzles around

their axis and different types of nozzles can be used)

5. Stability of the drone can be increased by designing

Octacopter Frame.

6. If weatherproofing is done then it can be used in any

season.

7. Monitoring of health of the crops can be done by using

camera mounted on the drone.

VI. CONCLUSION

In this paper we have described a design of the drone using

many other components which will be useful for the flight.

This design demonstrates that additive manufacturing



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technique can also be adopted for small scale purpose. This

paper also clarifies the doubts regarding platform to be used

for own suitable purpose.

NOMENCLATURE

UAV

Unmanned Aerial Vehicle

BLDC

Brushless Direct Current

ESC

Electronic Speed Controller

FCB

Flight Controller Board

PDB

Power Distribution Board

RF

Radio Frequency

PLA

Polylactic Acid

KV

KiloVolt

mAh

Milli Ampere Hour

GPS

Global Positioning System

gf

Grams of Force

kg

Kilogram

CAD

Computer Aided Design/Drawing

DC

Direct Current

AC

Alternating Current

PCB

Printed Circuit Board

RAM

Random Access Memory

FPV

First-Persion View

RC

Remote Controlled

CW

Clockwise

CCW

Counter-Clockwise

ACKNOWLEDGMENT

We are thankful to Prof. Pankaj Beldar of Department of

Mechanical Enginering (K.K. Wagh Institute of

Enginnering Education and Research) for helping us in all

of the stages.

REFERENCES

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[2] Dimosthenis C. Tsouros, Stamatia Bibi and Panagiotis

G. Sarigiannidis- “A Review on UAV Based

Applications for Precision Agriculture”.

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[3] Kang Yang, Guang You Yangand S Isi Huang Fu –

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Information 2019, 10, 349; doi:10.3390/info10110349

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